Modification of hydrochar derived from palm waste with thiourea to produce N, S co-doped activated carbon for supercapacitor

Abstract

This study examines modifying hydrochar from biomass to produce N, S codoped activated carbon for supercapacitor applications. Hydrochar was created from oil palm empty fruits bunch with the activating agent CaCl2 at 275 °C for 60 minutes. Hydrochar modification was carried out by the impregnation method in thiourea solution for 2 hours and impregnation ratio (1, 2, and 3) and continued the activation process at 800 °C for 120 minutes. The in-depth exploration of porosity unveiled a distinct pattern, as the progressive increase in impregnation ratio exerted a corresponding dampening effect on the activated carbon's surface area (151.57−234.56 m2 g−1). Subsequent engagement in electrochemical scrutiny, facilitated by a meticulously designed two-electrode system, revealed a pinnacle in capacitance performance, culminating at an impressive 135.12 F g−1at 0.5 A g−1 The energy and power densities achieved remarkable magnitudes in concert, scaling up to 3.4 Wh kg−1 and 202.6 W kg−1, respectively. Demonstrating robustness through the crucible of a 5000-cycle durability evaluation, the modified activated carbon-based supercapacitor emerged with unswerving capacitance retention and coulombic efficiency, each clocking in at a steadfast 106 % and 95 %. The discerning insights drawn from this inquiry underscore that the strategic incorporation of N, S-modification via thiourea engenders a qualitative enhancement within the supercapacitor's performance domain.

Keywords

• Biomass
• Carbonization
• Carbon material
• Energy storage
• Electrochemical performance